Effect of size of 7050 aluminum alloy sample on aging stress relaxation rate after quenching
Stress relaxation behavior of H-shaped samples with different scales of 7050 aluminum alloy during aging at 165 ℃ for 4 h was studied through FEM simulation and experimental verification methods.The results show that the simulation results are in good agreement with the experiment results,and the error is within 8.81％.The size effect mainly affects the aging stress relaxation rate through geometric characteristics and quenching stress.Within the experimental range,if the influence of initial stress is not considered,the scale of the sample does not affect the aging stress relaxation rate.Under the actual quenching stress,the stress relaxation rates of A,B,C,D and H points increase logarithmically with the increase of sample scale.For E,F and G points,the maximum stress relaxation rate occurs in the sample with 0.44 scale.The main reason is that the quenching stress changes with the sample size when the sample is in the range of 0.2-1.5 scales,which affects the stress relaxation process.When the sample is in the range of 1.5-5 scales,the quenching stress tends to be stable,resulting in a stable stress relaxation rate during the aging process and a weakened size effect.
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